Field of the Disclosure
The patent disclosure a method and structure to manufacture a glass substrate, and disclosed embodiments relate to one or more chip building a system on the glass substrate.
Brief Description of the Related Art
As is well known, microelectronic devices have a tendency to be minimized and thinned with its functional development and a semiconductor package mounted on a mother board is also following the tendency in order to realize a mounting of high integration.
When the geometric dimensions of the Integrated Circuits are scaled down, the cost per die is decreased while some aspects of performance are improved. The metal connections which connect the Integrated Circuit to other circuit or system components become of relative more importance and have, with the further miniaturization of the IC, an increasingly negative impact on the circuit performance. The parasitic capacitance and resistance of the metal interconnections increase, which degrades the chip performance significantly. Of most concern in this respect is the voltage drop along the power and ground buses and the RC delay of the critical signal paths. Attempts to reduce the resistance by using wider metal lines result in higher capacitance of these wires.
To solve this problem, the approach has been taken to develop low resistance metal (such as copper) for the wires while low dielectric materials are used in between signal lines.
Increased Input-Output (IO) combined with increased demands for high performance IC's has led to the development of Flip Chip Packages. Flip-chip technology fabricates bumps (typically Pb/Sn solders) on Al pads on chip and interconnect the bumps directly to the package media, which are usually ceramic or plastic based. The flip-chip is bonded face down to the package medium through the shortest path. These technologies can be applied not only to single-chip packaging, but also to higher or integrated levels of packaging in which the packages are larger and to more sophisticated substrates that accommodate several chips to form larger functional units.
The flip-chip technique, using an area array, has the advantage of achieving the highest density of interconnection to the device and a very low inductance interconnection to the package. However, pre-testability, post-bonding visual inspection, and TCE (Temperature Coefficient of Expansion) matching to avoid solder bump fatigue are still challenges.
Glass can be used as an interposer to bridge between one or more IC chips and a printed circuit board. In many respects, when used as an interposer/substrate and without the requirement for active devices, glass can be a good substitute for a silicon interposer. The advantages of glass in comparison to silicon as an interposer lie in its much lower material cost. Glass also has a CTE closely matched to silicon, so that reliability of interconnects, especially micro-bonds, can be expected to be quite good. Glass has some disadvantages in comparison to silicon—notably its lower thermal conductivity and the difficulty in forming Through Glass Vias (TGV's). Both of these topics are discussed elsewhere in this patent.